My .22 850 build

[fsae99]

So I started thinking how do I really make a setup that has versatility to push the 850 to max power, high shot count, or maybe both. Oh and it needs to accommodate the rear bottle 850 action stock project I want to do. Eric at Stalwart Arms agreed to work with me. Below is a picture of what was created. I'm waiting for it to be shipped to me so can't post new shot strings yet. With a Baker 850 adapter to on/off ASA to front bottle setup there are issues. Minuscule plenum and restriction to air flow are the biggest problems. Even with the 3 hole valve mod the baker adapter covers the vast majority of the 3 holes and it takes up most of the free space. I won't have those problems anymore.

With the current setup I have been getting 48 shots at 3000 psi starting down to 1800 psi reg pressure. This shoots 15.89 JSB's at 950 fps/32FPE. Right now I think I have some hammer bounce, and I cut down my spring guide so I have some travel on cocking before the spring is engaged. I have not bothered to try and tune since I had this thing being made.

From the new setup I'd like to get JSB 25.39's up to 950fps/50fpe for 50 shots.

I will have all the plenum I need to either go high power or high efficiency or both.


The rifle is shooting well at 950 fps here is a 24 shot string at 35yrds.





@imadunatic

[Tucobenedicto]

Nice,i am very courios to see the results 

[imadunatic]

I'm in... can't wait either.... How much volume we talking in that plenum? I did the rough math on mine and I think I'm near 18cc with the ASA, bored out baker adapter and valve body minus the poppet, that thing has got to be 3 times that (assuming it's bored out of course).

[fsae99]

I think ended up just over 50cc. That is part of the reason I think I can get to 50 shots at 50 FPE. I read in your thread that you were using 12.5 psi per shot while I'm currently at 25 psi per shot without boring the adapter. I'm probably at half or less of plenum right now. The other reason I think it will do 50 at 50 is that air should flow much better than the setup I have now. TO start with I'm going to leave the regulator at 1800 psi and then go from there. I hope to be able to get down to about 1500 psi or so.

I'm in... can't wait either.... How much volume we talking in that plenum? I did the rough math on mine and I think I'm near 18cc with the ASA, bored out baker adapter and valve body minus the poppet, that thing has got to be 3 times that (assuming it's bored out of course).

[stalwart]

I'm in... can't wait either.... How much volume we talking in that plenum? I did the rough math on mine and I think I'm near 18cc with the ASA, bored out baker adapter and valve body minus the poppet, that thing has got to be 3 times that (assuming it's bored out of course).

It's  bored out, alright! As I had to reach in through the valve hole... and good speed and feed creates wire, not chips... I had to break the setup down, often, to pick out the bird's nests inside. Turned out nice, though.

[fivestar45]

I'm in... can't wait either.... How much volume we talking in that plenum? I did the rough math on mine and I think I'm near 18cc with the ASA, bored out baker adapter and valve body minus the poppet, that thing has got to be 3 times that (assuming it's bored out of course).

It's  bored out, alright! As I had to reach in through the valve hole... and good speed and feed creates wire, not chips... I had to break the setup down, often, to pick out the bird's nests inside. Turned out nice, though.

Is the valve seat and stem still OEM?  A few years ago, when I re-did my 850 I found that to be the single biggest item that needed improvement.
http://www.gatewaytoairguns.org/GTA/index.php?topic=83664.msg802630#msg802630

[Tucobenedicto]

Hi Anthony,i am Fabio from the 850 resource,nice to see you 
I posted here my not-skilled man version of the valve too.
http://www.gatewaytoairguns.org/GTA/index.php?topic=119010.msg1179590#new

[fivestar45]

Hi Anthony,i am Fabio from the 850 resource,nice to see you 
I posted here my not-skilled man version of the valve too.
http://www.gatewaytoairguns.org/GTA/index.php?topic=119010.msg1179590#new

Hi Fabio 
Looks like my last post disappeared...Anyhow, I only wish that I would have thought of building my valve the way that you did. Brilliant!  And I might have gotten it to work on the first try, instead of the second.
Nice!

[imadunatic]

Anthony,

What don't you like about your V2 valve? Yours and Fabios both look like an improvement over the factory design, if I venture into stage 2, I'd like to be armed with all the R&D you and Fabio invested.

[Tucobenedicto]

Anthony,

What don't you like about your V2 valve? Yours and Fabios both look like an improvement over the factory design, if I venture into stage 2, I'd like to be armed with all the R&D you and Fabio invested.

The first Anthony poppet was made in red turcite and leaked at Co2 pressures,the second was made in delrin.

[stalwart]

I'm in... can't wait either.... How much volume we talking in that plenum? I did the rough math on mine and I think I'm near 18cc with the ASA, bored out baker adapter and valve body minus the poppet, that thing has got to be 3 times that (assuming it's bored out of course).

It's  bored out, alright! As I had to reach in through the valve hole... and good speed and feed creates wire, not chips... I had to break the setup down, often, to pick out the bird's nests inside. Turned out nice, though.

Is the valve seat and stem still OEM?  A few years ago, when I re-did my 850 I found that to be the single biggest item that needed improvement.
http://www.gatewaytoairguns.org/GTA/index.php?topic=83664.msg802630#msg802630

It is, but I don't expect that to last long. James is on this thing.

[Tucobenedicto]

You will not regreat,the original 850 valve design is a nightmare at pressures over 1200psi.

[fivestar45]

Anthony,

What don't you like about your V2 valve? Yours and Fabios both look like an improvement over the factory design, if I venture into stage 2, I'd like to be armed with all the R&D you and Fabio invested.

There is nothing that I don't like with the performance of the second go round of the valve. That said, Fabio thought up a way to do things simpler. I'm always in favor of getting good results with less work.

[fsae99]

My stock valve is holding at 1800 psi reg pressure, filled bottle and attached to gun, set on/off valve to on, left for a week at 3000 psi and no leaks. I would like to be able to use less spring pressure to lighten trigger and shot cycle. Currently my hammer hits pretty darn hard.

You will not regreat,the original 850 valve design is a nightmare at pressures over 1200psi.

[Tucobenedicto]

This is one of the reasons i modded my valve.there is a trigger mod explained in the 850 resource,it helps.

[imadunatic]

This is one of the reasons i modded my valve.there is a trigger mod explained in the 850 resource,it helps.

Did the triggers ever change on the 850? Mine is only 2 months old and it has an awesome trigger. I geared up to do the trigger mod I found on the resource, but it's very light and crisp as is. I thought maybe I got lucky or I don't know what everyone was trying to fix?

[Tucobenedicto]

The trigger mechanism of the 850 is very simple,not bad with the standard spring,becomes a lttle hard with hardest hammer spring.
I bought this trigger from germany,it helps,but the wire mod works about the same way.

[stalwart]

Is there a longer mag anywhere, of the same dimensions in all other ways, that would allow lengthening the slot... and allow use of the 34gr Jumbo beast and bullets? Maybe a .25 mag, that could be sleeved for .22?

[Tucobenedicto]

Unfortunately not,all magazines are same tickness.

[fsae99]

I did the wire mod and cut the spring guide. So currently not horrible.

Good news is that the plenum will be delivered today so if work does not get in the way I should at least get the gun put together today.

The flow should be much better than current setup that is restricted due to the baker adapter. I'm hoping to pick up fps just from that and I expect some more speed from actually having some plenum. Right now I think I have less than 9cc of plenum.

The trigger mechanism of the 850 is very simple,not bad with the standard spring,becomes a lttle hard with hardest hammer spring.
I bought this trigger from germany,it helps,but the wire mod works about the same way.